In many applications involving extractions or separations, the solids to be cleaned are rinsed or washed with solvents. Complications arise when the solids are air or moisture sensitive and the extracting liquids are liquified gases such as sulfur dioxide. For example, sulfur dioxide is a liquid only at temperatures below -10 C. If one wanted to use sulfur dioxide as a wash solution, unwanted moisture could easily condense and enter into the liquid and provide additional opportunity for contamination. This would be a serious problem even if the experiment could be conducted in a low humidity dry room. The water vapor present in low concentrations would condense into the cold liquid and thus react with the solid sample.